1. Field of Invention
This invention relates to a motor vehicle lock. The motor vehicle lock is especially suited as a side door lock, but can also be used for other motor vehicle locks which have at least two actuation chains.
2. Description of Related Art
The concept “actuation chain” quite generally designates a chain of action of forces between a first actuation element, such as a door handle, for example, and a second actuation element, such as, ultimately, a ratchet.
For motor vehicle locks, especially those for side doors of motor vehicles, providing two actuation chains from the outside door handle and the inside door handle to the ratchet is known. In a classic version of such a motor vehicle lock (German Patent Application DE 195 19 010 A1 and corresponding U.S. Pat. No. 5,921,595) the two actuation chains each have lever arrangements which are independent of one another and which act on the ratchet itself or on an actuation lever of the ratchet. For each actuation chain, there must be several levers in order to engage different operating states. Due to the host of existing levers, it is often necessary to arrange the levers distributed at a right angle to one another on a support structure which is made right-angled. Thus, the installation situation of such a motor vehicle lock changes.
For the motor vehicle lock which forms the starting point of this invention (German Patent Application DE 196 31 869 A1 and corresponding U.S. Pat. No. 6,062,613), it was recognized that a single control means is enough for the two actuation chains and complex lever constructions can be omitted if a flat plate-like configuration with elements which can move only lengthwise is chosen. For this reason, this motor vehicle lock has a control means as well as an internal actuation chain and an external actuation chain. These actuation chains, in the base state, are decoupled from the actuating lever of the ratchet and are coupled to the actuation lever by the control means depending on the operating state. Since the actuation chains are conventionally decoupled, there is moreover an emergency actuation device which couples the actuation chains to the actuation lever in an emergency, for example, when the control means fails.
The control means is made here as a control disk with cams for different operating states. To reach a certain operating state, it is necessary for the control disk to be moved mechanically or by a motor into defined positions. Sensors are necessary for defined reaching of the individual positions, for which reason the control is relatively complex. Furthermore, it is disadvantageous that the decoupled position of the actuation chains is implemented by one spring at a time. However, springs are complex to install, and moreover, are relatively susceptible to faults.
Furthermore, in practice, it has been shown that linearly movable elements of the actuation chains are not feasible over the long term. Wear and corrosion are difficult to handle there.
The expression “control means” here means the totality of components, such as levers, etc., which switch the internal actuation chain and/or the external actuation chain to be active or inactive with respect to actuation of the ratchet. This switching takes place depending on the different operating states. Different operating states are, for example, “Center lock” (CL), “Unlock” (UL), “Double lock” (DL) and “Child safety” (CS). In the UL operating state, the door can be opened by actuating the inside door handle and the outside door handle. In the CL operating state, the door cannot be opened by actuation of the outside door handle, but by actuation of the inside door handle. In the DS operating state the door cannot be opened either by actuation of the outside door handle or by actuation of the inside door handle. The door cannot be opened even after breaking into the vehicle. In the CS operating state, the door can be opened by actuating the outside door handle, but not by actuating the inside door handle.
Another known motor vehicle lock (German Patent DE 100 38 151 C2 and corresponding U.S. Pat. No. 6,568,722) has both a “DL” operating state in which the ratchet cannot be moved into its raised position, either by actuation of the outside door handle or by actuation of the inside door handle, and a “CL” operating state in which the ratchet can be moved into its raised position only by actuation of the inside door handle. The motor vehicle lock omits an inside locking button, the function of which is assumed by the inside door handle. For this purpose, a first stroke is assigned to the inside door handle and switches the control means of the motor vehicle lock from the “CL” operating state into the “UL” operating state. Then, the ratchet can be moved into its raised position by a second stroke.
A motor vehicle door lock (German Patent Application DE 101 39 975 A1 and corresponding U.S. Patent Application Publication 2003/0116977) is also known which has a central locking drive with which a control means can be switched between a “center lock” (CL) operating state and an “unlock” (UL) operating state. The ratchet in the UL operating state of the control means is normally shifted into the raised position which releases the latch by actuating an outside door handle. However, when the outside door handle in the CL operating state is actuated so quickly that the central locking drive cannot move the control means fast enough into the UL operating state, the central locking drive assumes the opening function. The ratchet is then moved into its raised position by the central locking drive.
Another known motor vehicle lock (European Patent Publication EP 0 710 755 B1) has a central locking drive with which a control means can be switched from the CL operating state into the UL operating state and vice versa. Moreover, the central locking drive is additionally set up as an opening drive with which a ratchet can be moved out of its engaged position which holds the latch into its raised position which releases the latch. The two functions (opening function and central locking function) of the central locking drive are achieved by a motor being coupled to the transmission element and driving it. For the central locking function, the transmission element is turned clockwise out of the initial position or counterclockwise back into the initial position. This movement defines a first range of motion of the transmission element to which the central locking function is assigned. The opening function is assigned to a second range of motion of the transmission element. This range of motion is defined by the swivelling of the transmission element out of the initial position counterclockwise and back into the initial position. In the initial position, the motor consequently acts on the transmission element in the middle, i.e., between the two ranges of motion. The use of two different ranges of motion for the different functions is unfavorable in this respect since, in this way, an altogether relatively large range of motion is necessary. Accordingly, the transmission element must be made accordingly large and a correspondingly large installation space is necessary.